2011 saw a record high in carbon dioxide emissions, with China’s contribution growing the most.

Climate change is a boon for one species, at least: The brown argus butterfly, previously rare, has been staking out more turf for itself as the areas north of its range become warmer and more hospitable.

With the chair of the Nuclear Regulatory Commission on his way out, the president nominated Allison Macfarlane to take his place.